Hey, Dack, this is a thoroughly brilliant tool - thank you very much. It does exactly what I would want a map editor to do.
I've been playing Civ since my Amiga days, and it's the first game I tried to edit as soon as I learned about Hex editors. I managed to understand enough of the SVE file, and could see the way the MAP file has 'layers', although I never got to understand it. Instead I edited the .exe file itself, which was fun. In 16 years I keep coming back to it because it's a very absorbing game, along with SWOS and Dungeon Master - classics which don't lose their appeal. I am currently writing an online SWOS editor in ASP.NET, as an exercise in the language and SQL, and I have considered doing the same for CIV. But now I don't need to, because this TerraForm editor does it all!
I always wanted to create a map where all the civilisations are in one part, and there's a beautiful land, just beyond the horizon, that is so full of resources that whoever gets there first stands a really good chance of winning. And now I have. (Thanks for sending the key so fast!).
My hex-edited CIV.exe file has different values for movement, defence and attack for the units, than the original game had. One thing I noticed - I added some units to the map in 3980BC (what Grand Dad would rightly call cheating, although it was for testing purposes), and they all had the original values for the first turn only, before reverting to the values I had set in the civ.exe file for subsequent moves. Strange, huh?